/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */

/*  CMetrics
 *  ========
 *  Copyright 2021 Eduardo Silva <eduardo@calyptia.com>
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

#include <cmetrics/cmt_atomic.h>
#include <windows.h>

/* This allows cmt_atomic_initialize to be automatically called 
 * as soon as the program starts if enabled.
 */

#ifdef CMT_ATOMIC_HAVE_AUTO_INITIALIZE

#pragma section(".CRT$XCU", read)

static void cmt_atomic_constructor(void);

__declspec(allocate(".CRT$XCU")) void (*initializer_)(void) = cmt_atomic_constructor;

__pragma(comment(linker,"/include:" "cmt_atomic_constructor_"))

static void cmt_atomic_constructor(void)
{
    cmt_atomic_initialize();
}

#endif

int cmt_atomic_initialize()
{
    return 0;
}

int cmt_atomic_compare_exchange(uint64_t *storage, 
                                       uint64_t old_value, uint64_t new_value)
{
    uint64_t result;

    result = _InterlockedCompareExchange64(storage, new_value, old_value);

    if (result != old_value) {
        return 0;
    }

    return 1;
}

void cmt_atomic_store(uint64_t *storage, uint64_t new_value)
{
    _InterlockedExchange64(storage, new_value);
}

uint64_t cmt_atomic_load(uint64_t *storage)
{
    return _InterlockedOr64(storage, 0);
}

